生成固定长度的随机字符和数字

 /**     * 生成固定长度的随机字符和数字     * @param len     * @return     */    public static String GetRandomCharAndNumber(int len) {        StringBuffer sb = new StringBuffer();        for (int i = 0; i <len; i++) {            int intRand = (int) (Math.random() * 52);            int numValue = (int) (Math.random() * 10);            char base = (intRand < 26) ? 'A' : 'a';            char c = (char) (base + intRand % 26);            if(numValue%2==0){                sb.append(c);            }else{                sb.append(numValue);            }        }        return sb.toString();    }